Research on Ultracapacitor-Battery Hybrid Power System

A hybrid power system composited by ultracapacitor, battery, and Bi-directional DC/DC converter is studied in this paper, and the ultracapacitor paralleled with battery pack through DC/DC converter. A 20kW hybrid power system is designed and applied to acceleration and regenerative braking of electric vehicle, and a H∞ robust control is designed to control the charge and discharge mode of the hybrid power system. Experimental results show that the proposed power system can meet both energy and peak power needs of electric vehicle, and the battery pack current has been controlled in reasonable limit which will be helpful to optimize the battery pack's working performance to get a longer cycling life, high efficiency and high economy.